Emancipation Day is celebrated on April 16, the day in 1862 that President Abraham Lincoln signed the congressional act into law.

Seven score and nine years ago, Abraham Lincoln signed the District of Columbia's Emancipation Act, making D.C. slaves the "First Freed" by the federal government. Now, Emancipation Day is -- for three days -- freeing you and me from filing our tax returns by April 15.

State and federal returns and taxes must be postmarked by 11:59 p.m. April 18 -- that would be Monday. So there's no need to visit a drop-box collection site by midnight today. "There won't be any services available," said Peter Hass, a regional spokesman for the U.S. Postal Service.

See, Emancipation Day was revived as a public holiday in the District of Columbia six years ago. It's celebrated on April 16, the day in 1862 that Lincoln signed the congressional act into law.

But since April 16 falls on a Saturday this year, the good people of D.C. will officially observe the holiday today. And according to the ever-logical federal tax code, District of Columbia holidays impact tax deadlines in the same way U.S. holidays and weekends do -- they postpone the filing date.

Oregon corporations, however, still must file their returns and pay taxes due today.

And you thought tax returns themselves were complicated.

If 72 additional hours aren't enough, here's more: Taxpayers who file for an extension get a couple extra days, too. Normally, returns filed under an extension are due Oct. 15. This year, that's a Saturday. That means the extension deadline is Oct. 17 for federal and state returns.

Mine eyes have seen the glory of 2011.

So, put off your calculating your adjusted gross income at least one more day. Spend the weekend marking the 150th anniversary of the start of the Civil War. We have Abe Lincoln to thank for all this.

He is, after all, the president who in August 1861 signed the Revenue Act -- the first federal income tax in U.S. history.